As we known, the measurement of junction-to-case thermal resistance (Rth-JC) of semiconductor power devices is very important. In this paper, an approach of transient dual interface method (TDIM) with gate-source voltage (Vgs) as the temperature sensitive electrical parameters (TSEP) was investigated for the measurement of Rth-JC of packaged SiC MOSFET. The measured Rth-JC value of packaged SiC MOSFET is in the range of 1.61 K/W to 1.76 K/W, and compared with the typical value of device specification, the maximum error is 5.29 %. The results show that the thermal resistance measurement of packaged SiC MOSFET by TDIM with Vgs as the TSEP is feasible, and it is of good accuracy and reproducibility.